In a power steering device configured to perform PWM control on a three-phase brushless motor to apply a steering force to a steering mechanism, a command current value to the three-phase brushless motor is subjected to feedback correction based on three-phase current values (phase current values). In a one-shunt current detection method, in order to obtain the three-phase current values, a bus current value between a bridge circuit configured to control drive of the three-phase brushless motor and a DC power supply is detected by a single current sensor so that the three-phase current values are reproduced from the DC bus current value. At this time, when PWM pulse widths of two phases are close to each other or the same as each other, it becomes difficult to sample the DC bus current value. As a result, the current value of each of the phases cannot be reproduced.
Therefore, in Patent Literature 1, there is disclosed a technology of performing a so-called pulse shift for shifting switch timings of the respective phases to prevent the two PWM pulse widths from being closer to each other.